C8051F352 Datasheet, PDF (197/234 Pages) Silicon Laboratories – 8 k ISP Flash MCU Family

C8051F350/1/2/3
22.1.3. Mode 2: 8-bit Counter/Timer with Auto-Reload
Mode 2 configures Timer 0 and Timer 1 to operate as 8-bit counter/timers with automatic reload of the start
value. TL0 holds the count and TH0 holds the reload value. When the counter in TL0 overflows from all
ones to 0x00, the timer overflow flag TF0 (TCON.5) is set and the counter in TL0 is reloaded from TH0. If
Timer 0 interrupts are enabled, an interrupt will occur when the TF0 flag is set. The reload value in TH0 is
not changed. TL0 must be initialized to the desired value before enabling the timer for the first count to be
correct. When in Mode 2, Timer 1 operates identically to Timer 0.
Both counter/timers are enabled and configured in Mode 2 in the same manner as Mode 0. Setting the
TR0 bit (TCON.4) enables the timer when either GATE0 (TMOD.3) is logic 0 or when the input signal /INT0
is active as defined by bit IN0PL in register IT01CF (see Section “12.5. External Interrupts’ on page 111 for
details on the external input signals /INT0 and /INT1).
CKCON
TTTTTTSS
3 3 2 2 1 0CC
MMMMMMA A
HLHL
10
TMOD
GCT TGCT T
A / 11A / 00
T T MM T T MM
E1 1 0E0 1 0
1
0
IT01CF
IIIIIIII
NNNNNNNN
11110000
PSSSPSSS
LLLLLLLL
210 210
Pre-scaled Clock
0
SYSCLK
0
1
1
T0
Crossbar
GATE0
TR0
TCLK
TL0
(8 bits)
/INT0
IN0PL _XOR
TH0
(8 bits)
Reload
Figure 22.2. T0 Mode 2 Block Diagram
TF1
TR1
TF0
TR0
IE1
IT1
IE0
IT0
Interrupt
Rev. 1.1
197